1. Field of the Invention
The present invention relates to aqueous solutions containing ubidecarenone. More specifically, it relates to aqueous solutions containing ubidecarenone in which a hydrogenated lecithin is incorporated.
2. Description of the Prior Art
Ubidecarenone (hereinafter referred to as CoQ.sub.10) is a substance which has been biochemically found to be involved in the myocardiac mitochondrial electron transport system and to play an important role in the production of energy. It has been found clinically to be effective in the improvement of congestive conditions, anginal conditions, etc., caused by the reduction in cardiac functions, such as chronic hypertension, ischemic disease, valvular disease, etc., and has come into wide clinical use. Said substance has heretofore been in the market often in the form of a solid preparation solely for oral administration, and this form itself has enabled the sufferer to take doses easily and has contributed to achieving a wide use of said substance.
In recent years, however, as a wider range of application of said substance has been discovered, it has been determined that the substance is more favorably presented as an aqueous solution. For example, the substance is poor in absorption through the intestinal track [Chem. Pharm. Bull., 20, 2585 (1972)], and it is clinically desired to administer orally as an aqueous syrup or to administer as an injectable preparation comprising an aqueous solution. It is also desirable that this should be administered as an aqueous topical preparation in pursuit of a therapeutic effect in the dermatological field.
However, CoQ.sub.10 is a lipid-soluble substance having a melting point of 48.degree.-52.degree. C. and is in the solid state an normal temperature. It is very difficult to be solubilized in water. Therefore, the present situation is such that a satisfactory aqueous preparation of the substance has not yet been obtained. For making it soluble in water, there has been a conventional method which comprises utilizing a nonionic surfactant, such as HCO-60 (produced by Nikko Chemical Co., Ltd.), but this requires a large amount of HCO-60, and as a result, when administered as an injectable preparation, it leads to the liberation of a histamine-like substance, and also when administered as an oral preparation, it brings about difficulty in the digestive tract and exhibits undesirable side effects such as diarrhea, etc.
Under such circumstances, the object of the present invention is to provide aqueous solutions containing CoQ.sub.10 which are prepared without using a nonionic surfactant such as HCO-60.